Double-acting proportional hydraulic pressure power amplifier



' Dec. 25, 1951 E T D 2,579,711

DOUBLE-ACTING PROPORTIONAL. HYDRAULIC PRESSURE POWER AMPLIFIER Filed Sept. 17, 1947 3 Sheets-Sheet 1 80 75 if 78 76 M 1; 74 73 o 7 4 77 8988 o 8 87 WOZ 99 6 6 .66 Z

INVENTOR Edwin Saud'e BY V ATTORNE.

Dec. 25, 1951 5 STAUDE 2,579,711

DOUBLE-ACTING PROPORTIONAL HYDRAULIC PRESSURE POWER AMPLIFIER Filed Sept. 17, 1947 3 Sheets-Sheet 2 INVENTOR BY Siaade Cum ATTO RN Patented Dec. 25, 1951 DOUBLE-ACTIN G PROPORTIONAL HYDRAU- LIC PRESSURE POWER AMPLIFIER Edwin G. Staude, Minneapolis, Minn. Application September 17, 1947, Serial No. 7 74,524

14 Claims.

My invention relates particularly to a double acting proportional pressure amplifier operated by a continuously flowing fluid to be used in connection with manual effort whereby a part of the pressure is transmitted opposing the manual control to retain the proportional feel of the increased pressure on the manual control valve. In accordance with my invention the proportionate pressure can be determined by the smaller area of a port or fluid passage, against which a closing or flow restricting valve acts with the short radius against a greater area of the vanes provided with a longer radius, thus multiplying the torque. Furthermore, no reverse action is required by the use of a reverse motion mechanism of the valve controlling mechanism such as used in my copending application Ser. No. 607,945, filed July 31, 1945, now Patent No. 2,554,843, granted May 29, 1951. This greatly simplifies the apparatus and, therefore, reduces the cost of the unit without the sacrifice of any desirable features.

I have designed the mechanism described herein by way of example, so it may be fabricated by the use of drop forgings or by any other method, such for instance as by the use of finished die castings of steel or any other metal, since all the passages are open and the parts may be assembled and bolted together with counter sunk cap screws.

The device is further simplified by the use of a large tube section clamped between the front and rear walls to provide an operating chamber within which the vanes operate.

The construction is such that the vanes used in the power amplifier may reciprocate or oscillate through an arc of 60 or more, this being the usual angle through which motion of this class is translated.

My present invention is more compact and more readily adaptable for mass production than in the previous devices, because all critical machine operations have been eliminated therefrom.

This is accomplished, also, by dividing the oscillating member in the center and providing two annular passages located side by side, each being connected to one of the two inlet and outlet passages controlled by a single valve member with its quadruple operating surfaces, so that one annular passage provides for pressure movement clockwise while the other annular passage provides for the exhaust by being connected to the return or outlet passage.

For anticlockwise movement the reverse takes place, so that the annular passage for the movement clockwise becomes the passage for the exhaust and the exhaust passage for the clockwise movement becomes the pressure passage for anticlockwise motion.

The two annular passages are separated from each other by a flat ring which is clamped in position when the two side walls of the oscillating member are bolted together.

There is the further advantage that by dividing the oscillating member substantially in the center, the depths of the annular passages will be only one half of what they would have to be if the passages were all formed on one side of the oscillating member, thereby providing a better and more practical construction.

There is the further advantage that with this construction, any number of vanes may be connected to the annular passages, since one passage serves for pressure clockwise while the other annular passage serves for exhaust and vice versa. The number of vanes which I use depends, of course, on the degree of movement required for the vanes which in turn determines the diameter of the oscillating member.

In order to show one example of my invention I have shown the device as applied to the power steering of an automobile but, obviously, it may be used, also, as an amplified power control for any automobile or aircraft accessory, such as brakes, rudders, elevators, or ailerons, or wherever a continuously flowing fluid circuit is used, that is a cruising circuit.

It is further evident thus with my present invention that no relief valve to control the maximum pressure of the pump is required, under ordinary conditions, but may be used if desired, as in a continuously flowing fluid circuit there is always sufficient seepage limiting the maximum pump pressure. Also, such seepage as may occur, regardless of the pressure at the moment, always drains back to the low pressure outlet passage. Therefore, in no case is it necessary to pack any high pressure present to prevent a leakage to the outlet.

It will be further noted that any manual force on the flow restricting valve is transmitted to act in the same direction as the power output, and, therefore, adds to the amount of work done, which is, however, always proportional to the manual input eifort, without in the slightest degree causing over-running of the power output.

It is further evident that the amplified power does not cut in unless the load is greater than the normal manual effort and only then in proportion to the required torque to perform the work without any la or delay because of the continuous how in the fluid circuit, which is always present to act instantly when required.

While my invention is capable of embodiment in many different forms to adapt it for the specific requirement, for the purpose of illustration I have shown only one application thereof for power steering, as an example, in the accompanying drawings, in which- Fig. 1 is a diagrammatic side elevation of a conventional automobile showing my invention applied to the steering mechanism thereof;

Fig. 2 is a vertical cross section taken on line 2--2 of Fig. 1;

Fig. 3 is a vertical section taken on line 3-3 of Fig. 2, with the central dividing ring removed;

Fig. 4 is a vertical section taken on line 4-4 of Fig. 2;

Fig. is a transverse section taken on line 5-5 of Fig. 3; and

Fig. 6 is a horizontal section taken on line 6-5 of Fig. 3.

In the drawings I have shown side walls 1 and 2 which form a casing in conjunction with an annular ring 3 located in a groove 4 in the wall I and a groove 5 in the wall 2, the walls and 2 being secured together by three bolts 6 and three bolts 1. The bolts 1 also serve to locate and secure together three chamber dividers 3, each of which is madein two pieces for convenience in assembling.

Located between the side walls and 2 and within the annular ring 3, I provide an oscillating member 6 having three vanes EU, I! and 12. These vanes divide the spaces within the annular ring 3 and between the chamber dividers 8 into six operating chambers l3, |4, |5, l6, l1 and I8. The oscillating member 9 is made in two parts l9 and 26, which are held together firmly by three outer cap screws 2| and four inner cap screws 22. The member I9 is provided with a hub 23 having therein a thin bushing 24. A roller bearing 25 fits over the hub 23 and is mounted in the wall I. The member I9 is, furthermore, provided with an annular passage 26 and a semicircular passage 21, which is connected with the annular passage 26 by a passage 28, and with an inlet port 33 as well as an outlet port 34.

A passage 29 connects the annular passage 26 with the operating chamber l4, a passage 36 connects the annular passage 26 with the operating chamber i5, and a passage 3| connects the annular passage 26 with the operatingchamber- H.

I A semi-circular passage 32 connects with the inlet port 33 and with the outlet port 34.

The passage 21 has a slightly flared outlet 35 as compared with an inlet 36 on the passage 21,

and the passage 32 has a slightly flared outlet 31 as compared to an inlet 38 on thepipe 32. This is done in order to be sure that a much greater force is exerted by the larger area at the fluid outlet of the passage 21 or 32 on the adjacent valve operating surface 55 or 56, than the inlet area 36 or 38 acting on the valve surface 51 or 58. As a result, a very definite feel is exerted in the manual operation of the mechanism. However, it will be understood that the inlet pressures on the opposite surfaces 51 and 58 are normally equal and tend to offset each other even when they are not in the normal middle position.

Referring to Fig. 6, it will be noted that an annular plate or ring 39 closes off the passage 26 from a passage 4| in the member 26 on the opposite side of the ring 39. The annular passage 4| is connected with the semi-circular passage 32 by a passage 42. In order to separate the annular passage 26 from the similar passage 4| in the member 26 I provide the annular plate or ring 39 fitting between the members 19 and 26, and to locate the same in position I provide small offsets 40 and 46a, which are located, respectively, on the member I9 and on the member 26. The passage 4| is also connected to the operating chamber |3 by a passage 43 (see Fig. 4), the chamber I6 is connected to the passage 4| by a passage 44, and the operating chamber I6 is connected to the annular passage 4| by a passage 45.

Thus, it will be noted that the annular passage 26 connects with the operating chambers l4, l5, l1 and 21, while the annular passage 4| connects with the operating chambers l3, l6, l8 and 32.

In other words, the annular passages 26 and 4| being separated by the partition 39 are two passages which are used alternately for pressure or exhaust. Therefore when pressure is directed through the passage 28 into the passage 26 through the closing of the surface 55 against the outlet 35 of the passage 21 and the closing of the intake fluid into the passage 32 by the surface 58 against the port opening 33, the pressure in the passage 26 will cause flow of fluid out through the ports 29, 36, 3| and move the vanes clockwise. During this time the fluid in the chambers l3, l6, l8 will exhaust through the ports 43, 44, 45 into the annular passage 4| then out through port 42 then through the passage 32 and out through the passage 34 into the return passage 12.

For clockwise motion of the vanes the exact reverse occurs so that the pressure passage 26 becomes the exhaust passage and the exhaust passage 4| becomes the pressure passage, all in very compact form which is simple to manufacture and assemble.

In order to control the flow of fluid through these various passages at will, I provide a valve member 46 mounted on a shaft 41 having a serrated end. The shaft 41 in this instance is the counter shaft of a conventional steering gear mechanism in which there is a steering wheel shaft 48 having thereon a worm 46 meshing with a pivotal anti-friction wheel 56 that operates in the worm 49 to rock an arm 5| forming a part of the shaft 41. Bearings 52 and 53 of the usual kind are provided for the shaft 41 as well as a conventional fluid sealing elastic ring 54 adjacent to the bearing 52.

The valve member 46 is provided with four operating surfaces 55, 56, 51 and 58. The valve member 46 is further held in neutral or inactive position by an U-shaped rubber pad 53. The member 26 is provided with a projection 66 supported in a ball bearing 6| mounted in the side wall 2, the said bearing 6| being held in position by a cap 62 secured by cap screws 63. A low pressure fluid sealing elastic ring 64 is also provided in the cap 62. From the aforesaid description it will be noted that the propection 6D acts as a bearing in conjunction with the hub 23 on the member I9. The shaft 66 has an extension 65 to provide for attaching an arm 66 thereto over a serrated surface on the extension 65. The arm 66 is held in position by a cap screw 61 and is the power output member of my pressure amplifier. The rubber pad 53 extends into a recess 68 in the members l9 and 26 and fits over a two part projection 66, 16 formed integrally with the members I9 and 26, respectively.

By operating a steering wheel 1| on the steering wheel shaft 48 in an anti-clockwise direction, the shaft 41 will be rotated anti-clockwise so as to rock the valve member 46 anti-clockwise, thus compressing the rubber pad 59 and tending to restrict the flow of the fluid out of the enlarged opening 35 of the passage 21 by means of a flat valve surface 55 on the valve member 4'3 and thus preventing the free flow of the fluid past the surface 55 into the outlet port 34. At the same time a flat surface 58 will restrict to a coordinate extent the free flow of fluid into the semi-circular passage 32 and thereby cause a pressure to build up in the passage 21. The liquid will then pass out through the passage 28 into the annular passage 26 and out through the passages 29, 30 and 3|, into the operating chambers I4, I5 and IT to act against the vanes 10, II and I2. As soon as the vanes start to move, the fluid on the opposite sides of the vanes in the operating chambers I3, I6 and 18 will pass out through the passages43, 44 and 45, into the annular passage 4! through the passage 42 into the passage 62 and out past the valve surface 56 on the valve member 46 and out through the port 34, which is connected by a passage 12 to an outlet nipple '13.

A small copper pipe 14 connects with a supply tank 15 which is connected by a pipe I6 with the inlet port of a pump ll driven from a fan belt I8 on a fan 18 carried by a hub 86 driven from a shaft 8! of an internal combustion engine 82 provided for driving the automobile. The hub 80 has a pulley 83 for the belt I8 which also passes over a pulley 84 on a hub 85 of a pump shaft 86. An outlet .port 8'! is provided on the pump TI and this is connected with an inlet nipple 88 (see Fig. 3') by a small pipe 88. The inlet nipple 88 is connected to a passage 90 in the wall member I and the passage 90 is connected with the inlet port 33.

In order to equalize the pressures on the oscillating member 9, a portion of the wall Si in the member 26 is cut away (see Fig. 2) so that the pressure liquid entering at the opposite side will not bind the oscillating member 9.

As the high pressure fluid drains towards the center around the bearing 61 I provide a small duct or channel 95 (see Fig. 2) which connects with the low pressure outlet 34. I also provide a duct or channel 96 which connects the low pressure fluid around the bearing with the low pressure 34 (see Fig. 2).

I also provide the usual connecting rod 99 which is pivotally attached to the arm 66 at one end and to the usual steering knuckle I00 at the other end.

In the event that no fluid is in circulation due to pump inactivity, for any cause, one or the other of the surfaces 55 or 56 will bear against the corresponding one of the outlet surfaces or 31 which will then act as a stop, and in that event the manual effort on the steering wheel will continue to operate the oscillating member 9 and thereby continue to operate the device manually.

It will be noted that the surfaces 51 and 58 operate to restrict or close off the passages 33 and 38-, so that all the surfaces 55, 56, 51 and 58 of the valve member 46 operate against pressures derived from the inlet pressure.

By connecting the return pipe I4 to the tank 15, in the manner described, I am able to eliminate automatically bleeding air out of the system when starting, because such air as is in the system will rise to the surface in the tank :5 and not follow out through the pipe 16.

Also, by means of the tank I5, which is provided with the usual air vent, the operation of the device manually is facilitated as it permits exhausting the fluid in the system into the tank in the event of the inactivity of the pump TI.

The three vanes I6, I I and [2 increase the torque for the same size vanes, as compared with the construction shown in my copending two-vane application Ser. No. 607,945 above referred to.

While I have described my invention above in detail I wish it to be understood that many changes may be made therein without departing from the spirit of the same.

I claifn:

1. A double acting manual control and fluid power amplifier having passages and connections for receiving fluid circulation and exhausting the same, a fluid compartment for receiving said fluid, a movable wall therein, an oscillating member connecting said wall to a work-performing element, said member comprising two disc-like parts secured together having annular passages therein, respectively, including ports, leading from pressure inlet to said wall, valve means associated with said manual control for restricting the flow in said passages with a resultant back pressure on the valve means 'for controlling the pressure acting against the wall to move the wall in the desired direction, said manually operated means moving in the same direction as said wall and operable in either direction from an initial inactive position for operating said valve means by applying said area so as to restrict the fluid circulation, the back pressure area of said valve means being smaller than the area on said movable wall so as to move said wall manually and by the pressure of the restricted flow of pressure fluid, result in a smaller follow-up back pressure for feel on the manual control shaft.

2. A double acting manual control and fluid power amplifier having fluid inlet and fluid outlet passages, a fluid compartment for receiving said fluid, an oscillating movable wall therein, an oscillating member connecting said wall to a work-performing element, said member comprising two disc-like parts secured together having annular passages therein, respectively, leading from the fluid inlet to said wall, oscillating valve means associated with said wall for restricting the flow in said passages with a resultant back pressure on the valve means for controlling the pressure acting against the wall to move the wall in the desired direction, said manually operated means moving in the same direction as said wall and operable in either direction from an initial inactive position for operating said valve means by applying said area so as to restrict the fluid circulation, the back pressure area of said valve means being smaller than the area on said movable wall so as to move said wall manually and by the pressure of the restricted flow of pressure fiuid, and result in a smaller follow-up back pressure forfeel on the manual control.

3. A double acting manual control and fluid power amplifier having fluid inlet and fluid outletpassages, a fluid compartment for receiving said fluid, an oscillating movable wall therein, an oscillating member connecting said wall to a work-performing element, said member comprising two disc-like parts secured together having annular passages therein, respectively, leading from said fluid inlet to said wall, oscillating valve means associated with said wall for restricting the flow in said passages with a resultant back pressure on the valve means for controlling the pressure acting against the wall to move the wall in the desired direction, said manually operated means moving in the same direction as said wall and operable in either direction from an initial inactive position for operating said valve means by applying said area so as to restrict the fluid circulation, the back pressure area being smaller than the area on said movable wall so as to move said wall manually and by th pressure of the restricted flow of pressure fluid, and result in a smaller follow-up back pressure for feel on the manual control.

4. A double acting manual control and fluid power amplifier having fluid inlet and fluid outlet passages, a plurality of fluid compartments for receiving said fluid, an oscillating movable trolling the pressure acting against the walls to move the walls in the desired direction, said manually operated means moving in the same direction as said wall and operable in each direction from an initial inactive position for operating said valve means by applying said area so as to restrict the fluid circulation, the back pressure area of said valve means being smaller than the area on said movable walls so as to move said walls manually and by the pressure of the re stricted flow of pressure fluid.

5. A double acting fluid power amplifier including a fluid source for establishing a pressure fluid, an oscillating member having a pair of adjacent annular passages, each of said passages serving alternately as the fluid pressure and the fluid exhaust passage, fluid inlet and fluid outlet passages connecting said annular passages with said source, said oscillating member having double acting vanes against which fluid pressure acts to perform work in either direction, a casing for said oscillating member and said vanes having vane chambers therein and passages connecting said annular passages with said vane chambers, and a valve member for controllin the fluid pressure and the exhaust to and from 'said vanes through said annular passages.

6. A combined reversible manual control and fluid pressure power amplifier having a receiving fluid inlet and an exhaust outlet, a casing, a manual power input shaft, a manual and fluid power output shaft, an oscillating member se-- cured to the manual and fluid power output shaft, said oscillating member being made in two parts for convenience in assembling, vanes secured to said oscillating member operating in said casing, fixed walls in said casing located between said vanes, chambers between said fixed walls and said vanes, a pair of annular passages within said oscillating member said annular pas sages being separated from each other by a partition, each one of said annular passages serving as a fluid pressure passage and the other as the exhaust passage alternately, ports connecting one of said annular passages to said chambers in said casing on one side of said vanes and ports from the other annular passage to the other side of said vanes, a pair of semi-annular passages both connecting the said fluid inlet with said exhaust outlet, one of said semi-annular passages being connected by a port to one of said annular passages and the other semi-annular passage being connected by a port to the other annular passage, a lost motion connection between said manual power input shaft and said oscillating memher, a valve having multiple surfaces and mounted on said manual power input shaft for controlling the flow of fluid in said semi-annular passages and resilient means for controlling lost motion between said manual power input shaft and said oscillating member and returning said valve to pressure releasing position when manual effort on said manual power input shaft is reduced.

7. A combined reversible manual control and fluid pressure power amplifier having a fluid inlet and an exhaust outlet, a casing, a double acting work performing member actuated by fluid pressure, fluid inlet and exhaust outlet passages for said work performing member, a manual power input shaft, a manual and fluid power output shaft, an oscillating member made in two halves and connected to said manual and fluid power output shaft and said work performing member, a resilient lost motion connection between said manual power input shaft and said oscillating member, a pair of passages both connecting the said fluid inlet with the said exhaust outlet, one of said pasages being also connected by a passage with said fluid pressure in said work performing member and the other passage also by a passage with said exhaust passage in said work performing member, a valve having four surfaces and mounted on said manual power input shaft, said valve when moved against said resilient lost motion connection, acting to restrict the flow of fluid in the inlet of one of said passages and also restrict the flow of the fluid outlet in the other passage, said resilient member serving to return said valve to inactive position when manual effort on said manual power input shaft is reduced.

8. A combined reversible manual control and fluid pressure power amplifier having a fluid inlet and an exhaust outlet, a casing, a reversible work performing member located within said casing, fluid pressure and exhaust passages for said work performing member, a manual power input shaft, a manual and fluid power output shaft, an oscillating member made in two halves and secured to said manual and fluid output shaft, and with said work performing member, a lost motion connection between said manual power input shaft and said oscillating member a pair of semi-annular passages within said oscillating member, both semi-annular passages connecting the said fluid inlet with the said exhaust outlet, one of said semi-annular passages being connected by a passage with said fluid pressure passage in said work performing member, and the other semi-annular passage being connected by a passage to said exhaust passage in said work performing member, a valve having multiple surfaces and mounted on said manual power input shaft, said valve being operated through said lost motion connection with said oscillating member by means of a resilient member to control the flow of fluid in both semi-annular passages.

9. A combined reversible manual control and fluid pressure power amplifier having a fluid inlet and an exhaust outlet, a casing, a reversible work performing member located within said casing, fluid pressure and exhaust passages used alternately for said work performing member, a manual power input shaft, a manual and fluid pressure power output shaft, an oscillating member made in two halves and secured to said manual and fluid pressure output shaft and connected with the work performing member, a lost motion connection between said manual power input shaft and said oscillating member, a pair of passages within said oscillating member, both passages connecting with said fluid inlet and said exhaust outlet, one of said passages being also connected with said fluid pressure passage in said work performing member and the other passage also connected with said exhaust passage in said work performing member, a valve having multiple surfaces and mounted on said manual power input shaft and operated through said lost motion connection with said oscillating member by means of a resilient member to control the flow of fluid in both passages.

10. A combined reversible manual control and fluid pressure power amplifier having a fluid inlet and an exhaust outlet, a casing, a reversible work performing member, fluid pressure and exhaust passages used alternately for said work performing member, a manual power input shaft, a manual and fluid pressure power output shaft, an oscillating member made in two halves and secured to said manual and fluid pressure output shaft and connected with said work performing member, a resilient lost motion connection between said manual power input shaft and said oscillating member, passages within said oscillating member connecting said fluid inlet with said fluid outlet and said fluid pressure and exhaust passages in said work performing member, a valve having multiple surfaces and operating against the direction of fluid flow for controlling the flow of fluid in said passages, said valve being mounted on said manual power input shaft and operated through said resilient lost motion connection of said oscillating member with said manual power input member through said valve.

11. A combined reversible manual control and fluid pressure power amplifier having a fluid inlet and an exhaust outlet, a casing, a double act-= ing work performing member actuated by fluid pressure, fluid inlet and exhaust outlet passages for said work performing member, a manual power input shaft, a manual and fluid power output shaft, an oscillating member made in two halves and connected to said manual and fluid power output shaft and said work performing member, a resilient lost motion connection between said manual power input shaft and said oscillating member, a pair of passages both conmeeting the said fluid inlet with the said exhaust outlet, one of said passages being also connected by a passage with said fluid pressure in said Work performing member and the other passage also by a passage with said exhaust passage in said work performing member, a valve having four surfaces and mounted on said manual power input shaft, said valve being of the type that receives fluid from a single passage, divides the same into two streams and exhausts the same into a single passage, said valve when moved against said resilient lost motion connection, acting to restrict the flow of fluid in the inlet of one of said passages and also restrict the flow of the fluid outlet in the other passage, said resilient member serving to return said valve to inactive position when manual effort on said manual power input shaft is reduced.

12. A combined reversible manual control and fluid pressure power amplifier having a fluid inlet and an exhaust outlet, a casing, a reversible work performing member located within said casing, fluid pressure and exhaust passages for said work performing member, a manual power input shaft, a manual and fluid power output shaft, an oscillating member made in two halves and secured to said manual and fluid output shaft, and with said work performing member, a lost motion connection between said manual power input shaft and said oscillating member, a pair of semiannular passages within said oscillating member, both semi-annular passages connecting the said fluid inlet with the said exhaust outlet, one of said semi-annular passages being connected by a.

10 passage with said fluid pressure passage in said work performing member, and the other semiannular passage being connected by a passage to said exhaust passage in said work performing member, a valve having multiple surfaces and mounted on said manual power input shaft, said valve being of the type that receives fluid from a single passage, divides the same into two streams and exhausts the same into a single passage and operated through said lost motion connection with said oscillating member by means of a resilient member to control the flow of fluid to both semi-annular passages.

13. A combined reversible manual control and fluid pressure power amplifier having a fluid inlet and an exhaust outlet, a casing, a reversible work performing member located within said casing, fluid pressure and exhaust passages used alternately for said work performing member, a manual power input shaft, a manual and fluid pressure power output shaft, an oscillating member made in two halves and secured to said manual and fluid pressure output shaft and connected with the work performing member, a lost motion connection between said manual power input shaft and said oscillating member, a pair of passages within said oscillating member, both passages connecting with said fluid inlet and said exhaust outlet, one of said passages being also connected with said fluid pressure passage in said Work performing member and the other passage also connected with said exhaust passage in said work performing member, a valve having multiple surfaces arranged to receive fluid from a single passage and divide the same into two streams and exhaust the same into a single passage and mounted on said manual power iiiput shaft and operated through said lost motion connection with said oscillating member by means of a resilient member to control the now of fluid in both passages.

14. A combined reversible manual control and fluid pressure power amplifier having a fluid inlet and an exhaust outlet, a casing, an oscillating work performing member, fluid pressure and exhaust passages used alternately for said work performing member, a manual power input shaft, a manual and fluid pressure power output shaft, said oscillating work performing member being made in two halves and secured to said manual and fluid pressure output shaft and connected with said work performing member, a resilient lost motion connection between said manual power input shaft and said oscillating member, passages within said oscillating member connecting said fluid inlet with said fluid outlet and said fluid pressure and exhaust passages in said work performing member, a valve having multiple surfaces with two surfaces operating simultaneously against the direction of fluid flow for controlling the flow of fluid in said passages, said valve being mounted on said manual power input shaft and operated through said resilient lost motion connection of said oscillating member with said manual power input member through said valve.

EDWIN G. STAUDE.

Name Date Jessup Feb. 20, 1934 Number 

